While, you can see the same design as the Shield of David (Star of David), the symbol of the Jews, in various places in Japan.
In Mie prefecture, Japan, is located Ise grand shrine which was built for the Imperial House of Japan, and a symbol which looks very much like the Shield of David is carved on all the lamps along the approaches to the shrine.

The Japanese call it Kagome crest, which means basket reticulation in Japanese. This was named because the crest looks like the reticulation of Japanese traditional bamboo basket.
The lamps at Ise grand shrine were built and offered from the donators to the shrine after the World War 2. The Kagome crest is also carved at a monument of Manai shrine, the former (original) Ise grand shrine located in Kyoto. This monument is also offered to the shrine.

In Japan, people have been using crests which look like the Shield of David since very old days. For instance, Asa-no-ha crest, which also resembles the Shield of David, has been used widely as symbols for clothes since about Kamakura-era (the 12-14th century C.E.). And Kagome crest was used by Komiya clan and Magaribuchi clan, etc., who are descendants of emperor Seiwa (the 9th century C.E.).
We can also see the symbols which resemble the Shield of David as regalias of several cities of Japan. The city regalias of Nishi-no-miya city (Hyogo prefecture), Oomuta city (Fukuoka), Otaru city (Hokkaido), Wakkanai city (Hokkaido), and Fukuchiyama city (Kyoto) are all in the shape of 6 pointed star, and resemble the Shield of David very much.
But did they really originated from Jewish Shield of David? Or, did they only happen to resemble?
You can recall the badge of American sheriff to be the same design as the Jewish Shield of David, but it does not mean that he is a Jew. The same thing could be said concerning the crests in Japan. The design of six pointed star was used widely in various countries from old days because of its geometrical beauty.
In Israel, this symbol is discovered as a design without national significance in old remains; for instance, Shield of David is discovered in a synagogue in Capernaum, Israel, built in about second century C.E.. But it was only a design and was not unique to the Jews. Even among other nations than the Jews, this design It was since the 17th century C.E. when this design started to be used generally as the formal symbol for the Jews.
So, it is difficult to judge whether or not the Japanese design of six pointed star originated from the Jewish Shield of David.